This invention relates to a moving coil type loudspeaker unit and, more particularly, to a coil mount structure of a moving coil type loudspeaker which is easy to assemble and can provide a stable electro-acoustic reproduction characteristic.
In a conventional loudspeaker unit of moving coil type, an example of which is shown in FIG. 1, a magnetic circuit is constituted with a permanent magnet 1 and a center pole 2. A coil bobbin 3 is movably retained. A voice coil 4 is wound around the voice coil bobbin 3 in such a manner that there is provided with an annular magnetic gap 1a between a pole piece of the permanent magnet 1 and the voice coil 4. A cone-shaped diaphragm 5 has an inner neck section connected to the voice coil bobbin 3 and an outer circumferential portion adhered to a frame 6 of the loudspeaker unit. A damper 7 has an inner circumferential portion connected to the voice coil bobbin 3 and an outer circumferential portion adhered to a base portion of the frame 6. The aforementioned loudspeaker unit has been assembled in the following manner.
An annular spacer jig is also put coaxially around the center pole 2, and then the voice coil bobbin 3 is inserted into the jig and a yoke on which the frame 6 is mounted is positioned at a desired position with suitable jig. Thereafter, the inner and outer circumferential portions of the damper 7 are adhered to the voice coil bobbin 3 and the base portion of the frame 6 by means of an adhesive agent, respectively as shown in FIG. 2. The inner neck section of the cone-shaped diaphram and the outer circumferential portion thereof are adhered to the voice coil bobbin 3 and the frame 6 by means of the adhesive agent, respectively. Subsequently, the jig is removed and a dust cap 11 is adhered to an upper end portion of the voice coil bobbin 3. Voice coil leads 8 are then connected to a VC terminal 9. All of the above adhesion works must be performed with other suitable jigs.
With such a loudspeaker unit as described above, however, since there is a large number of portions to be adhered by means of the adhesive agent, the adhered portions must be maintained in fixed condition by means of the jigs until these portions are completely adhered. This is disadvantageous in that the assembly thereof requires a large number of jigs and therefore the manufacturing efficiency is low. Therefore, the conventional loudspeaker unit is not suitable to mass produce.